Cai Bolin, Li Zhenhui, Ma Manting, Wang Zhijun, Han Peigong, Abdalla Bahareldin A, Nie Qinghua, Zhang Xiquan
Department of Animal Genetics, Breeding and Reproduction, College of Animal Science, South China Agricultural UniversityGuangzhou, China.
Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, and Key Laboratory of Chicken Genetics, Breeding and Reproduction, Ministry of AgricultureGuangzhou, China.
Front Physiol. 2017 Apr 20;8:230. doi: 10.3389/fphys.2017.00230. eCollection 2017.
Long non-coding RNAs (lncRNAs) play important roles in epigenetic regulation of skeletal muscle development. In our previous RNA-seq study (accession number GSE58755), we found that lncRNA-Six1 is an lncRNA that is differentially expressed between White Recessive Rock (WRR) and Xinghua (XH) chicken. In this study, we have further demonstrated that lncRNA-Six1 is located 432 bp upstream of the gene encoding the protein Six homeobox 1 (). A dual-luciferase reporter assay identified that lncRNA-Six1 overlaps the proximal promoter. In lncRNA-Six1, a micropeptide of about 7.26 kDa was found to play an important role in the lncRNA-Six1 activity. Overexpression of lncRNA-Six1 promoted the mRNA and protein expression level of the gene, while knockdown of lncRNA-Six1 inhibited expression. Moreover, tissue expression profiles showed that both the lncRNA-Six1 and the mRNA were highly expressed in chicken breast tissue. LncRNA-Six1 overexpression promoted cell proliferation and induced cell division. Conversely, its loss of function inhibited cell proliferation and reduced cell viability. Similar effects were observed after overexpression or knockdown of the gene. In addition, overexpression or knockdown of promoted or inhibited, respectively, the expression levels of muscle-growth-related genes, such as , and . Taken together, these data demonstrate that lncRNA-Six1 carries out -acting regulation of the protein-encoding gene, and encodes a micropeptide to activate gene, thus promoting cell proliferation and being involved in muscle growth.
长链非编码RNA（lncRNAs）在骨骼肌发育的表观遗传调控中发挥着重要作用。在我们之前的RNA测序研究（登录号GSE58755）中，我们发现lncRNA-Six1是一种在白洛克（WRR）鸡和杏花鸡（XH）之间差异表达的lncRNA。在本研究中，我们进一步证明lncRNA-Six1位于编码Six同源盒蛋白1（Six homeobox 1）的基因上游432 bp处。双荧光素酶报告基因检测确定lncRNA-Six1与Six同源盒蛋白1近端启动子重叠。在lncRNA-Six1中，发现一个约7.26 kDa的微肽在lncRNA-Six1活性中起重要作用。lncRNA-Six1的过表达促进了Six同源盒蛋白1基因的mRNA和蛋白表达水平，而lncRNA-Six1的敲低则抑制了Six同源盒蛋白1的表达。此外，组织表达谱显示lncRNA-Six1和Six同源盒蛋白1的mRNA在鸡胸肉组织中均高表达。lncRNA-Six1的过表达促进细胞增殖并诱导细胞分裂。相反，其功能丧失抑制细胞增殖并降低细胞活力。在Six同源盒蛋白1基因过表达或敲低后也观察到类似的效果。此外，Six同源盒蛋白1的过表达或敲低分别促进或抑制了肌肉生长相关基因（如MyoD、MyoG和MRF4）的表达水平。综上所述，这些数据表明lncRNA-Six1对编码Six同源盒蛋白1的基因进行反式作用调控，并编码一种微肽来激活Six同源盒蛋白1基因，从而促进细胞增殖并参与肌肉生长。
